Engine rebuild? what to do?

[vwluv10338]

Well here is my situation and I need imput form people:

PROBLEMS:-SR20 redtop-Turbo is blown, lots of shaft play and makes bad noises when boosting- engine was sluggish untill I changed the oil. I could smell gas in the oil. Ran fine for about two weeks afer oil change now its sluggish again- compression test showed around 150-155psi across most of the cyclinders (didnt do one that was under strut brase) however, I didnt have the throttle open like I was supposed to so not sure how good those numbers are.

POSSIBLE SOLUTIONS:- I can get a "good" shortblock from one place for $800+ shipping and $900 from a place with about an 8 hour round trip.- Can get a shortblock from a guy with bad rings for about $450 shipped- I can get a CTC Motorsports race block fully built for $4k

SOLUTION PROBLEMS:- I have never built an engine before (done head work but never shortblock stuff)- I dont have a job right now but will be starting work in about a week and a half.- I have $1200 in the bank and will get $500 for my b-day- I am in mechanic classes and we have to build an engine but that is not for a year and a half- Do I buy the busted block, rebuild it or have it rebuilt with forged components and then swap it with mine and rebuild mine in my class- Do I buy a "working" shortblock, swap it with mine, then build mine forged in my class- Do I start working, take out a loan, buy the race block, and buy whatever the hell turbo I want

Help me out here people.

Eric

[RobDET]

Hey man you checked the injector O rings right? as far as the oil/gas problem i had the same thing but it was because i had torn an injector O ring. I was filling the bottom end up with gas. You could have a small tear. It's a cheap fix and worth a try.

[RobDET]

Also if it was me i'de want to build my own motor. That way you could be sure that everything was straight. If you let anyone else do it it'll be kinda like a "sealed box" Who knows whats really in there...

[vwluv10338]

Well most of my experience has been on old bugs so I dont know much about fuel injection. From what I know it is a pain to get the injectors out but I guess I will just have to read the FSM. Where would I get new injector seals?

Also, after reading more posts and thinking I figured something out. Whatever happened to get fuel in the oil happened about a week or so before the bogging. It seems that my car runs fine and then after a week the gas breaks down the oil and my car starts to bog. Change the oil, drive a week and the same thing.

Now, could this be what toasted my turbo? Say, for argument, that I blow an injector seal, gas in my oil, oil breaks down, bearings in oil die, shaftplay?

Eric

[Redline240]

Solution:

Find out why your getting gas in your oil...after, and only after that is fixed get a new or used turbo with minimum shaft play...your engine isn't blown, i think your getting carried away...check your o rings out on your injectors, maybe your piston rings...you probaly have plenty of money to fix it right now so don't worry too much yet...

Redline

[vwluv10338]

New o-rings are going in tomorrow and I will change the oil and see what happens.

Eric

[RobDET]

when you put the o rings in be SURE to lubricate them with a little bit of oil. They WILL tear if you don't lube them. And turn the screws in evenly on both sides.

[vwluv10338]

Cool. I take the injectors all out and then push them out of the rail? That is what the FSM said but I dont think it was the rail but I cant remember what the manual called it. I remember it said not to pull them out from the connector. Any other advice?

Eric

[Onizuka]

Im rebuilding my motor right now because i wanted to put a metal headgasket on, its not that hard (and i have a pathetic selection of handtools only). If you can afford the down time you might as well, it will be like a new motor again

[RobDET]

the injectors will probilby be a PITA to get out... i took off the metal caps (2 screws) then put vice grips on teh side of the plastic part of the injectors and wiggled... eventuially they will come out.

putting them in is easier... just use a little oil and they slide most of the way in. you use the cap to get them all the way down.

[vwluv10338]

I do have another car to drive but no where to work. I dont have a garage to use to pull the motor. I am still thinking of getting the $400 shortblock I found because I got more info from the guy and I could still save it for later even if my engine is ok.

Eric

[ItzGenX]

Not meaning to hijack the thread, but my #2 injector seems to be leaky. I replaced the O-rings twice on it, and I can pull it out and the O-rings seem fine. My oil smells like gas also. Also, what type of USDM O-ring can I replace them with, and where can I get them?

[vwluv10338]

If you are asking what 0-rings to use which ones had you used the last two times you replaced them. You can go to Pepboys or whatever and get the rings for a KA24de (The DOHC from '91+) or a Z32 TT but then I guess gor the Z32 you would have to buy a set of six.

Eric

[RobDET]

i got sentra SE-R ones. The TTz32 ones looked too big. The NA Z ones were the same as the SE-R tho if i remember right. I had the dealer pull several different types.

It looks like nissan only uses 2. You want the ones shaped like a doughnut not a cylinder.

[vwluv10338]

Heavy Throttle says to use the DOHC KA and the Z32 TT in their F.A.Q. section. Also, I am a mechanic student for toyota and my instructor made a good point. The injector o-ring does not control fuel input into the engine. It just seals the injector in. He said check the injector using some sort of fuel pressure gauge and check to see that the injectors are all working correctly. I can see in an injector is leaking that could be my problem. I didnt think the o-ring would do it but thinking about it if that seal is leaking then under vacuum the car should run lean as it is sucking air in and under boost I guess it would run rich because air would be escaping around the injector.

Eric

[vwluv10338]

P.S. I was thinking that the o-ring would be dumping fuel into the cyclinders that werent firing and that was where the extra fuel was comming from but that wouldnt happen if the o-rings were bad, only if the injector is bad. Just thinking.

EDIT: I forgot about valves and that a leaky injector wouldnt be dumping into the cyclinder because the valves would be closed. Possible cause for gas in oil, leaky valve seals?

Eric

[RobDET]

Ahh but the 240sx has side feed injectors... Your instructor was tihnking of top feed injectors.

On our cars their is a rubber doughnut just abov where the tube in the fuel rail is and there is an o ring right at the bottom in the intake manifold

if fuel is flowing into one of the intake runners at 255LPH then you would definately have too mutch fule to burn. As soon as the valve opened the fuel would get into the cylinder and wash down the sides past the rings. That is what is known as washing a cylinder. it's a very bad thing and THAT could require a rebiuld.

[RobDET]

oah and valve seals are where the valve goes through the head. They prevent oil from entering the intake runner. The valve seat is where the valve seals against the head.

[I H8 UR DSM]

Well here is my situation and I need imput form people:

PROBLEMS:-SR20 redtop-Turbo is blown, lots of shaft play and makes bad noises when boosting- engine was sluggish untill I changed the oil. I could smell gas in the oil. Ran fine for about two weeks afer oil change now its sluggish again- compression test showed around 150-155psi across most of the cyclinders (didnt do one that was under strut brase) however, I didnt have the throttle open like I was supposed to so not sure how good those numbers are.

POSSIBLE SOLUTIONS:- I can get a "good" shortblock from one place for $800+ shipping and $900 from a place with about an 8 hour round trip.- Can get a shortblock from a guy with bad rings for about $450 shipped- I can get a CTC Motorsports race block fully built for $4k

SOLUTION PROBLEMS:- I have never built an engine before (done head work but never shortblock stuff)- I dont have a job right now but will be starting work in about a week and a half.- I have $1200 in the bank and will get $500 for my b-day- I am in mechanic classes and we have to build an engine but that is not for a year and a half- Do I buy the busted block, rebuild it or have it rebuilt with forged components and then swap it with mine and rebuild mine in my class- Do I buy a "working" shortblock, swap it with mine, then build mine forged in my class- Do I start working, take out a loan, buy the race block, and buy whatever the hell turbo I want

Help me out here people.

Eric

Before you get any sort of 'block' work, make sure CTC or whoever you go through has an SR20det tourqe plate. I have 'heard' that they assemble the blocks without one...which isnt a good thing...it is hearsay (Sp?) though, so maybe they have one.....JWT has one, We have one, and i think one other person has one...but i'd be wary of having anyone do block work w/out a sr20det tourqe plate.

[vwluv10338]

Ahh but the 240sx has side feed injectors... Your instructor was tihnking of top feed injectors.

On our cars their is a rubber doughnut just abov where the tube in the fuel rail is and there is an o ring right at the bottom in the intake manifold

if fuel is flowing into one of the intake runners at 255LPH then you would definately have too mutch fule to burn. As soon as the valve opened the fuel would get into the cylinder and wash down the sides past the rings. That is what is known as washing a cylinder. it's a very bad thing and THAT could require a rebiuld.

Ok then, o-rings first it is. My instructor said it could also be my MAF. Just another place to check.

Eric

[ItzGenX]

Quote »If you are asking what 0-rings to use which ones had you used the last two times you replaced them. You can go to Pepboys or whatever and get the rings for a KA24de (The DOHC from '91+) or a Z32 TT but then I guess gor the Z32 you would have to buy a set of six.[/quote]

I used my spare ones from my engine gasket kit. None of my rings are ripped or even has a scar on them at all. Could it be that my injector is straight leaking? Where can I get a replacement 370CC injector (new or used at a good price) without hitting up ebay and paying for all four or shipped from Japan.

[RobDET]

Hey Itz...

Did you try posting in the forsale/WTB section? i'll bet everyone that has upgraded injectors in their SR is trying to sell them. Also a lot of KA-T guys snatch them up so they might know a good srouce. HT says they are the same as z32 'purple top' injectors whatever that means (the injectors are purple on top)

[vwluv10338]

OK, well the o-rings are not my problem. I was going to order them but I took out my fuel rail and pressurized it by turning the car on and if they were going to leak they would have. However, my #3 injector was different from the others. The others had a plastic donut-looking piece on the bottom and the number three injector had a plastic piece that looked like a star with the points bent around under it. It looked stock with the same green dot on it that the others had. Anyone know anything about this?

Overall, back to my fuel problem:-not the injector o-rings- MAF seems ok since it runs ok but if I unplug it more problems occur than before- My compression is fine, I did another test the correct way. All cycl had between 155 to 160.- did find an exhaust leak between manifold and turbo because I could see it leaking smoke after I used seafoam

Overall: - blown exhaust gasket from extra vibration from the enormous amount of shaftplay I have?- not injectors, not MAF, why do I still have gas in my oil?

Frustrated Eric

[vwluv10338]

oah and valve seals are where the valve goes through the head. They prevent oil from entering the intake runner. The valve seat is where the valve seals against the head.

Right. Couldnt gas be getting into the head through the valve seals when I am boosting? But I guess when I was off boost I would be getting oil in my gas and since I dont see smoke out of my tailpipe I dont know if that could be it. I am just trying to think where else the gas could be comming from.

Eric

[RobDET]

i'm confused about your "different" injector thing. I'de lay money that it has something to do with that... but i've only taken my injectors out of the rail... I've never taken the rail off the car. Sorry you are in a place i don't know about there ...

I really can't think of any other palce for fuel to be getting into the oil though. I mean it has to come from the injectors or the rail and wash down the sides...

Hey it's a long shot but are you absolutely sure you ahve the lines on the fuel rail right?

The fule filter line goes straight to the rail. The Feul pressure regulator side goes straight to the hardline

[vwluv10338]

Everything on the rail is fine. My swap was done by Heavy Throttle and has been fine up untill about a month ago. I dont think it is the injector o-rings because with the rail off and pressurized if it was leaking into the cyclinders I would have seen something leaking. Also, my spark plugs look fine, they dont even look like my car is running ritch. I have no idea where to go from here.

Eric

[Nathan]

Jesse, do you mean a torque plate for boring and honing? I didn't think you SR guys did that much because of the nikasil cylinder linings...

[I H8 UR DSM]

well you're correct that 'most' people dont And most people dont build their motors, let alone, bore/hone or sleeve. But the CTC block is sleeved and fully built...and like i said , im not 'sure' if they are using a tourqe plate : \

Trying to find a machine shop that has a tourqe plate is a freakin search and a half (unless your near JWT), so instead of sending the block accross the country (which shipping would rape me), we decided to purchase the Tourqe Plate for purposes of building my motor, and we have it now, to rent out to other shops, or build SR20det motors for customers.

Im not promising there are only 2 others in the US, im just saying, we searched around a bit, and couldnt find any besides them...and a lot of asking around to different people in the industry. So you guys now know of someone else who has one

I was just suggesting he make sure before he bought their race block...i dont know much about CTC anymore, their site changed so much, and it almost looks like they are only doing online store ordering or something..i couldnt even find an email addy on their site.

but you are correct in the fact that most people arent building motors with high levels of HP that they are worrying about sleeving the motor, and have a need for a tourqe plate...but for anyone who is building a motor, do not do it at a machine shop w/out the tourqe plate for the SR20det.

[Nathan]

I know it's not your area of expertise as much...but what do you think about torque plates and KA's? If I want it torque plate bored and honed it'll have to go to either JWT or Sunbelt (I think they have one) I haven't found a machine shop in Dallas that does have one. I'd like the best job possible done, but there are a lot of motors doing just fine without being bored and honed with a torque plate. That's really cool that you guys bought one of the plates, thats a nice thing to be able to offer. I'd be really irritated if I spent 4 grand on a block that wasn't torque plate bored and honed...As for CTC, they never returned my calls when I was looking for a motor so I dont like them.

[I H8 UR DSM]

I know it's not your area of expertise as much...but what do you think about torque plates and KA's? If I want it torque plate bored and honed it'll have to go to either JWT or Sunbelt (I think they have one) I haven't found a machine shop in Dallas that does have one. I'd like the best job possible done, but there are a lot of motors doing just fine without being bored and honed with a torque plate. That's really cool that you guys bought one of the plates, thats a nice thing to be able to offer. I'd be really irritated if I spent 4 grand on a block that wasn't torque plate bored and honed...As for CTC, they never returned my calls when I was looking for a motor so I dont like them.

yea i dont know ctc's deal, or if they are even a 'shop' anymore.

As far as the tourqe plate...if you dont use one, your really just doing an injustice, no matter what, you will have distortion when u attatch the head to the block, just by definition ya know...I am the worst KA newby so, this might sound retarded, but i dont even know the blocks construction. The SR having an aluminum block is going to distort more than a Iron block, (*i dont have the exact numbers here), but the dsm motors iron blocks distort .05(or .005?, whatever lol) i believe when the head is attached...so you have a gap in the front of two cylinders, and too close on the sides, so u will have blowby (im sure you know what i mean even though im explaining it real bad), so even though its minescule (sp?) the cylinders are 'oval' slightly, and not perfectly round....the tourqe plate is the only thing that you can do to make sure you have that block machined perfectly.

Those CTC blocks might even be done JWT..??..who knows, i doubt they are doing it in house, but i could be wrong.

So if you have an iron block its going to be 'less', but still important..i know people who learned the hard way w/ the dsm's, even though they are iron block, and blown many motors....of course they arent stock hp motors. But if your going to do it, do it the right way, and be safe....you 'can' machine the block w/out the TP, but it will not be *right* if u know what i mean...and yes, maybe you will get by, but there is no way to get away from the fact that those cylinders will not be machined perfectly, ya know...its going to distort somewhat when u attatch the head. and the only way to compensate for that is to use a tourqe plate when machining.

I'd suggest sending it to someone w/ the plate. But thats just me...you may not *have to*....but.................